


Chemical Reactions

by beetle_mate



Category: Sherlock (TV)
Genre: Angst, Developing Relationship, Experiments, Fluff, Friends to Lovers, Grumpy John, Humor, Insecure Sherlock, John-centric, M/M, Mice, Miscommunication, Non-Consensual Drug Use, Non-consensual experimentation, animal abuse kind of, did i mention mice?, no really it does get angsty
Language: English
Status: In-Progress
Published: 2017-08-04
Updated: 2017-08-11
Packaged: 2018-12-11 03:06:39
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 4,483
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11705520
Author URL: https://archiveofourown.org/users/beetle_mate/pseuds/beetle_mate
Summary: Wherein John worries he is the subject of one of Sherlock's experiments and is unsure if his developing feelings towards the man are genuine or artificial. There is fluff and angst and mice.





	1. Chapter One

John padded downstairs, not bothering to suppress a jaw-cracking yawn. The flat was quiet, watery mid-morning sunlight filtered through the blinds. Bits of dust floated through the yellow swatches of light and the smell of something Mrs. Hudson had baked lingered faintly in the air.

 At times 221b felt downright cozy, John decided, reaching into the cabinet to pull out a mug for tea. His hand closed around something small and furry  -- and warm. And _squeaking_?

Someone in the flat made a rather unmanly sound and before John knew what was happening, a small white mouse had leaped from his hand onto the counter. It scurried towards a plate of biscuits Mrs. Hudson had brought up the evening before.

Stupefied, John watched as the small white intruder picked a crumbled bit of biscuit up in his tiny pink paws. It nibbled enthusiastically, beady red eyes staring directly into John’s soul as its mouth worked feverishly over the  pastry.

John was caught between disgust and anger with anger winning out – surely this was the result of some experiment left to degrade too long on the counter – but he recovered quickly and knew he needed to act fast in order to catch the rodent.

The rodent, however, appeared to be in no such hurry. John took stepped tentatively forward, arms held out, anticipating a chase. The mouse continued rotating the morsel until there was nothing left and reached for another piece.

Amidst the disgust, John couldn’t help but feel a little irritated by the creature’s utter lack of fear of him. He grabbed an oven glove out of the drawer and held it threateningly over the intruder.

The mouse nibbled on, unimpressed, expression clearly reading “What of it, mate?”

“Cheeky bastard,” John muttered and snatched the mouse up by the tail. To his surprise it hardly reacted, simply dangled from John’s gloved grip – and still refused to let go of the bit of biscuit clenched between its tiny pink hands.

“Oh, for christ’s—“

John stomped over to the window and wrenched it open. He flung the furry white interloper down into the alley, feeling maybe just the tiniest bit vengeful as he did so.

He shut the window and turned around to survey the flat with a sigh. They really needed to be more careful about leaving food and entrails out…

Spectacle over, John made tea and toast and cheerily dumped the rest of the biscuits into the trash. One little mouse was not going to ruin his day off. Hell, he was honestly surprised this was the first time he’d encountered a rodent, given Sherlock’s (nonexistant) cleaning habits and penchant for leaving organic matter lying about for hours on end.

John settled down into his chair with his tea.

The chair squeaked indignantly.

The tea went flying, the toast fell jam-side down onto the carpet, and John found himself making a very undignified noise for the second time that morning.

The two small trespassers paid him no mind, however, as they were busy. Incredibly, vigorously busy in fact.

John gaped at the two white mice, who were enthusiastically going at it. _In his bloody chair!_ They paid him the same regard as their recently vaulted brethren, which was none at all. They ignored him completely as he swore and stomped back to the kitchen for the glove, everything starting to look a bit red.

John’s pocket vibrated and he angrily whipped his phone out as he fumbled for the glove.

_Don’t kill the mice. –SH_

John blinked at his phone and resisted the urge to glance surrepticiously around the flat.

 _Do NOT tell me these are part of an experiment._ he shot back.

_They should be docile and easy to handle. Please return any escapees to the enclosure  set up in the bathroom. -SH_

John seethed.

_You utter prat. Of course they got loose. One almost bit me!_

_I highly doubt that. -SH_

John’s anger was quickly joined by suspicion; a combination of emotions so linked to his relationship with Sherlock that John had considered inventing a name for it. 

_Wait_

_Why_ are _they so docile?_

_And what kind of experment could you possible need them for?_

_As usual, John, your complete lack of imagination borders on embarrassing. –SH_

John used the glove to scoop up the two mice – _who were still bloody going at it –_ and carried them into the bathroom, holding them out in front of him the way a bachelor might handle a dirty diaper. He found an empty cage sitting in the bathtub with a small door on its side pried a few inches open. He deposited the amorous rodents inside and snapped the door securely shut. He dug a safety pin out of the drawer and secured it to the door as an added measure.

 _How many are there?_ he typed furiously.

He waited several minutes for a response, and when one didn’t come he threw the phone onto the counter, muttering things that would make Mrs. Hudson blush. Armed with a scowl, a small wastebasket, and a flyswatter, John settled in for a day of mouse-hunting. Honestly, it was hardly the strangest way he’d spent a day off. Life was rarely dull these days.

***

He’d caught three more mice by the time Sherlock returned that evening.

“Sherlock,” John began, using a tone every parent is taught at the parent initiation ceremony. The one universally intended to instill dread, fear, and a desire to confess.

“John, I don’t have time for whatever dull remarks you’re going to make about cleanliness,” Sherlock waved him off, setting down a plastic bag on the table. “The mice are of no concern. I can tell from your posture that you were able to find all six.”

John’s question caught in his throat as a wave of scent wafted from the bag Sherlock had brought in with him. It smelled suspiciously like food.

“Five,” John said, crossing his arms. He was caught between annoyance at the mouse situation and confusion (along with a bit of concern) about Sherlock’s choice to buy food unprompted.

Sherlock’s pale eyes shot up to him for the first time since he’d entered the room.

Despite himself, John felt a pang of guilt. “I, er, threw one out the window.”

The look of betrayal Sherlock sent his way belonged somewhere arctic.

“Well it was before I knew they part of an experiment,” John grumbled, before re-thinking his stance. “Wait – _I_ am not the one in the wrong here. You can’t have mice running around out flat, Sherlock. What would Mrs. Hudson say?”

Sherlock waved him off again, turning his attention and slight pout back to John’s laptop, which he’d snatched off the table. “It won’t happen again, I’ll reinforce the cage. I thought they may have been motivated enough to escape the standard pet store model.”

John shook his head but it was more at himself than Sherlock. The things he put up with. Why was he even surprised Sherlock had decided to purposely infect their house with tiny furry experiments? “Please,” he tried, “just keep them from going at it in my chair.”

“Merely a side effect,” Sherlock murmured, typing away on John’s laptop.

John frowned at that, but the smell of the take-away was an effective distraction. “Is that Thai?” he asked cautiously, edging nearer the bag.

“Yes. It’s for you. I assumed you would have been too busy in your reconnaissance to make anything.”

Accurate, but a bit of a surprise that Sherlock had considered that. It was probably the closest to an apology John was going to get. And he _was_ pretty hungry.

It was John’s favorite. He ate ravenously, realizing only once the first noodles passed his lips that he hadn’t eaten since the toast much earlier. The detective rattled off some facts about a case Lestrade had brought to him involving a missing businessman, possibly connected to an opiate drug ring. John’s aggravation slipped away as he slurped his noodles and the circumstances of the case drew him in

He made a small content noise as he bit into a particularly delicious bit of duck, and then noticed after a few beats that Sherlock had stopped talking. He glanced over, finding the taller man staring at him over the laptop.

John frowned. “Do I have something—“ He swiped a napkin over his lips.

Sherlock didn’t reply, and his eyes snapped back to the glowing screen in front of him. He resumed talking, even while he simultaneously clacked away on the keyboard at breakneck speed.

John sighed and learned back in his chair. Food went a long way in mending bridges in John’s book. “Thanks for the dinner,” he yawned, stretching out a bit more. “Almost makes up for having to dig a mouse out of your sock index.”

The unmasked horror on Sherlock’s face drew a few deserved chuckles from John. Immediately, the ghost of a smile lifted a corner of Sherlock’s lips, belying his affected alarm. The detective shot a look at John out of the corner of his eye, a silent acknowledgement that all was forgiven and he was grateful.

John flipped on the telly, still smiling. These moments with Sherlock were like small but precious, polished little gems. People wondered (and he sometimes wondered too) how he lived with and spent so much time with Sherlock. The man could be acerbic, dismissive, self-absorbed, and downright rude.

He also made John an integral part of his work and made him feel alive and said he preferred John’s tea to anyone else’s and played screeching pieces on the violin to wake John from his nightmares. And sometimes brought John food, apparently.

There were little moments of shared grins and laughter. Looks that expressed things that didn’t need words. The unvoiced understanding that they were in this, whatever _this_ was, together. Friendship, in all its strange and brilliant glory.

It was something John couldn’t explain to other people who knew Sherlock, because as far as he knew he was the only one allowed entrance to this secret corner in the vast and intricate labyrinth that was Sherlock’s life.

Thinking this without thinking it, John could feel the last vestiges of his irritation with his flatmate dissolve into a warmth that spread throughout his body. He could feel Sherlock’s eyes on him and noticed he was still smiling, but couldn’t be arsed to stop or care. At the moment, John was truly happy to share his life with his impossible, brilliant idiot of a friend.

And sometimes 221b _could_ feel downright cozy.


	2. Chapter Two

The mice did not escape again. At John’s unrelenting insistence the cage were moved from the bathtub to the table. John took pains to eat everything at the counter and glare as often as possible at the small white intruders.

Every once in a while, Sherlock would use a dropper to add several droplets of liquid to the water bottle fixed to the side of the cage. He would then submit the mice to a variety of tests involving loud noises, various strong-smelling chemicals, and even a rangy-looking cat from the alley that he’d smuggled inside when John wasn’t paying attention.

John had put an end to that right away.

“What are you giving them?” John finally asked, watching Sherlock jot down notes in his small but uncramped handwriting. One of the mice ran so fast in its spinning wheel that John was amazed its little heart didn’t give out. 

“I’m testing their responses to a variety of threatening stimuli.”

John frowned. “But you’re putting something in their water as well. I’ve seen you do it.”

Sherlock didn’t answer. The man seemed totally absorbed in watching the seconds tick away on a stopwatch, but John knew him well enough by now to tell when he was avoiding a question.

“Well, at least give them a proper meal, I don’t think I’ve seen them eat anything yet.” He pulled on his coat as he prepared to leave for work.

Sherlock ignored him and he rolled his eyes, shutting the door behind him.

***

The case involving the missing businessman was quickly becoming one of John’s least favorite cases. One evening Sherlock returned to the flat stinking of sickly sweet opium. Rationally, John knew that Sherlock was not using drugs. But the smell provoked a strange visceral response in him and images of Sherlock with a needle in his arm jumped to mind, unbidden, causing an irrational burst of anger and adrenaline to course through him. Before he knew it he was on his feet.

“Where the  _hell_  where you?” He’d ground out, bristling and crowding the detective like an angry bulldog.

Sherlock froze, although his expression remained impassive.“You needn’t be so concerned, _doctor_.” Sarcasm was evident in his words, though the smirk didn’t quite reach his pale eyes and he seemed tense in John’s aggressively close proximity. “I was investigating the case.”

Ah, yes. Of course. John pulled away and his posture softened, but he maintained a close eye on Sherlock’s actions. Anytime drugs and Sherlock were involved, John took no chances, even if the man was simply gathering evidence from less the than savory characters involved.

Under John’s close scrutiny, the detective’s actions seemed uncharacteristically awkward and hesitant as he pulled off his scarf and coat and hung them up. He didn’t meet John’s gaze.

John trusted Sherlock, he really did. He knew that the man had no desire to fall back on old habits.  Perhaps John _was_ being a bit hard on him. Then again, he sometimes felt like he shared his flat a bloody toddler. The man couldn’t feed himself regularly, for christ’s sake. And he had an such aggravating tendency to delicately balance on the line between fine and _not fine._

“Tea?” Sherlock asked, his rumbling boice sounding almost coy as he slunk away from the other man’s evaluating stare.

The question caught John off guard. Sherlock _never_ made tea.

His surprise must have shown. Sherlock rolled his eyes and began grabbing the enecessary items out of the cupboards. “Yes, I know _how_ to make tea.” 

John shrugged, though he was slightly chagrined. “Sure, yeah, that’d be nice,” he replied, settling back down in his chair with his book. “Did you learn anything at least when you were at – wherever you were?”

Sherlock rattled off several things he had gleaned from his visit to the opium dealer’s house. Several minutes later a steaming mug was settled on the table beside John, who had set down his book again and was letting the facts of the case wash over him. As so often happened in their relationship, John had to simply trust the the wave of information Sherlock sent his way would be eventually picked over, distilled, and rearranged into a cohesive narrative.

While he may not entirely trust the man around drugs, he certainly trusted him in

“Cheers.” John smiled up at him and received a tight nod in return. He sipped his tea and was surprised to find it good. Very good.

The faintest noise – a tiny _hmmph –_ pricked his ears and he watched Sherlock lower himself into the couch just a little too gently.

“What is it?”

Sherlock pointedly ignored him in favor of opening the laptop. He was sitting just a little too stiffly, John noticed.

“Sherlock, are you hurt?”

Again, the man in question pretended to be too absorbed in the screen in front of him to respond.

“ _Sherlock_.” The bite in his name forced the detective to return his gaze.

“There was an incident with a junkie, nothing serious.” He sounded put-upon, bored.

“An _incident_ with a _junkie?”_ John demanded. “And you were just – what, not going to mention it?”

“It’s fine,” Sherlock replied levelly. “Nothing you need to worry about.”

John barked a laugh, causing Sherlock’s eyes to snap up. “Nothing to worry about? Christ, Sherlock, you’re _all_ I worry about.” John realized how this sounded only as it left his mouth, but he chose to ignore it. He stepped purposely into the dark haired man’s personal space for the second time that evening. “Let me see.”

He could have been imaging it, but he thought he saw a faint flush creeping up the other man’s neck, whether in response to John’s words or his demands is anyone’s guess.

“That’s really not necessary,” Sherlock replied in the clipped and formal way had of talking when he got uncomfortable.

John scowled, crossing his arms and planting himself stubbornly. He was a bloody doctor after all, and he took care of him in nearly every other aspect.

“Well, let me make sure they did all right then.”

When Sherlock realized that John did not appear to be moving any time soon, he rolled his eyes again but did shift the computer off his lap onto the table. He stood and gingerly untucked his shirt (ripped on the side with a small dark stain, John now noticed) from his trousers, pulling it up to reveal a jagged cut about an inch and a half wide just below Sherlock’s left ribcage. It had stopped bleeding but there was some residue of dried blood and John had the impression Sherlock had hastily wiped it down with something before forgetting about it altogether.

All –or at least most – of John’s irritation dissipated, concern welling up inside him in its place. He gently rucked the shirt up a bit further, being careful not to rip away any parts that might be stuck toi the wound.  

“It’s not too deep,” the doctor murmured, crouching down to get a better look. “But god knows what kind of diseases might be floating around that place, Sherlock.” He couldn’t help the way his voice softened and changed, couldn’t help but feel a little self-concious about the level of concern he was showing for a man whose sence of self-preservation was nil.

He inspected the cut and the rest of Sherlock’s exposed torso to be sure there were no other injuries the man was withholding form him, eyes skimming appraisinly over the pale skin. Sherlock shifted, tense under the doctor’s wandering hands and eyes.

“You’re lucky you don’t need stitches,”John said with no real anger. “What the hell happened?”

“You know I loathe to repeat myself,” Sherlock said shortly, but then relinquished and sighed. “He may have construed my questioning as some kind of threat. I admit that I – misclaculated his reactions.” His words were low and quick, as if he was ready for the discussion to be over as soon as possible. He didn’t, however, move to escape from John’s grip on his bared skin.

John mentally kicked himself for not being there. He’d had to work, yes, but Sherlock was just so much better off if he had backup going into these situations.  If nothing else, he needed someone to attempt to reign him in and then patch him up when he inevitably refused to listen.

“Well, take your shirt off. You’re an idiot for not cleaning this out sooner.” It was too bad it had to be John’s favorite shirt of Sherlock’s. Wait, since when did he have a favorite shirt of Sherlock’s?

Sherlock’s narrowed eyes peered at him over his shoulder over his shoulder for a couple beats, but then, to John’s surprise, he complied without a fuss. John fetched his doctor’s bag from his room, returning to find the shirtless detective perched uncomfortably on the arm of couch, his pale eyes back to being glued to the computer he’d returned to his lap.

John cleaned the cut gently but thoroughly. Idly, he couldn’t help but wonder if this was the closest (physically) he’d ever been to his flatmate for an extended period of time, and partialy undressed at that. Certainly Sherlock had a habit of wandering the house in various states of undress, but this was the first time John had actually touched his bare skin.

The cut wasn’t too deep, looked like a quick jab that Sherlock just hadn’t moved quickly enough to fully evade. It wasn’t bleeding any logner, although it had saturated the frayed entrace point of the shirt Sherlock had been wearing. Under normal circumstaces the doctor wouldn’t be terribly concerned with a cut such as this, but the introduction of drugs and the unscrupulous characters involved in the incident made every worry and doubt bubble up in his mind.

 John placed a hand on Sherlock’s back to steady him as he applied antiseptic, noticing how the man’s muscles contracted and stiffened under his fingertips. The tap-tap-tapping of the keyboard ceased for just a moment.   

“You alright? I’m not hurting you?” John murmured, pausing briefly to try and read his friend’s expression.

Sherlock shook his head tightly, a stray curl bouncing.

Now that the initial concern over the injury had gone, John couldn’t help wondered how many people had been this close to Sherlock before. The man, whether it was an act or not, always seemed to confident and sure of himself, but right now seemed about ready to jump out of his skin, the tension evident in the lines of his body. Yet he didn’t writhe out of John’s grasp like a sullen child, as John had half-expected, but sat very still and allowed his doctor to work, although the slight frown on his face clearly expressed his dissatisfaction with the arrangement.

An image of Sherlock as a scowling, scrawny child popped into his head unbidden – a bright eyed, curly-headed boy forced to sit still during an endless supper when he’d rather be up in his room working on an experiment.

A wave of intense affection for Sherlock swept through John. The warmth spread instantly form fingertips to toes, and he felt the strongest sense of empathy for the man that he may have every experienced. For a moment, he felt like he really understood him and why he was the way he was, and it was a lovely feleing.

The moment was so intense (and pleasant) that he couldn’t help but breathe a quiet, involuntary puff of laughter, which instantly raised a swatch of gooseflesh on his patient’s exposed skin before him. He hadn’t relized he was leaning quite so close. The keyboard tapping faltered again.

Suddenly John felt like there was helium in his stomach. And he felt warm and a little lightheaded. He noticed Sherlock had sucked in a breath and hadn’t let it out yet.  

He glanced up to take in his friend’s expression again. Sherlock stared straight ahead, but John could tell he was aware of the doctor’s every move the way a nervous dog keeps a threat in its peripherals. John could clearly see a flush spread from his sharp cheekbones down his long, exposed neck.  

Sherlock no longer looked impassive, was no longer frowning slightly. His eyes were wide, nervous, practically fearful.

The expression had an incredible effect on John,  who instinctively wanted to comfort and assure the other man that everything was fine, still riding the wave of empathy that had crashed through him. Before he knew what he was doing, he was reaching up to gently cup Sherlock’s chip and turn his face towards him.

“Are you sure you’re alright?” he asked again, although his voice sounded off, too low. 

Sherlock’s pale eyes finally fixed directly onto his and John felt their gaze like a physical jolt. They were wide and more vulnerable looking than John had ever seen. He felt very hot all of a sudden, could feel his face warming to match Sherlock’s (had he ever seen Sherlock _blush_ before?) and was very aware of how close he was to the man – practically caressing  him – and when had Shelock leaned in so close? There didn’t seem to be enough oxygen. There was a buzzing in his skin that exploded in the places where he was still touching the Sherlock, who was tense, but turning even more  now, or was John imagining that? He seemed to be shifting minutely towards John the way a flower tracks the sun. Time felt slow and John’s thoughts were thick, sluggish. All he knew was: it felt good. Very good. Lovely, in fact, maybe the best thing John had every felt.

The closeness sudden;y seemed unbearbly intimate – Sherlock’s gaze was unwavering, nervous, and at the same time as if he’d just made a deuction and was waiting for John;s mind to catch up, but all John’s mind could think was that he would only need to lean in a few more inches –

What the hell?

He pulled away, sucking in a breath and dropping his hands from Sherlock’s body as if it had burned them.

“Well, ah, that’s all better then,” he stammered, getting quickly to his feet. The room swam a bit – god, maybe he _was_ getting ill – as he took a couple steps backward. “I think I’m just going to, er, pop out for a bit.” He couldn’t bring himself to look in Sherlock’s direction to catalogue a response before all but fleeing the flat.

Outside, the crisp air felt wonderful on his flushed skin. He chose a direction at random and started off at a brisk pace.

_Jesus Christ_ , what had gotten into him?

His body felt as if it was filled with helium, his heart was jackhammer in his chest.

He strode quickly but without direction, letting the rhythm of his strides bring his body back under control.

What had just _happened_?

He’d been patching up his friend –flatmate, completely platonic partner, _Sherlock_ – and then out of nowhere things had gotten – intense, and then John had felt light-headed and had some kind of mini panic attack?

John turned a corner quickly, narrowly missing a cursing teen on a skateboard. He shook his head to rid the images of Sherlock’s expression that kept flashing unbidden into his head.

Clearly his blood sugar was low or something. He hadn’t eaten since that morning after all.

The thing was, he didn’t feel hungry at all. In fact, his stomach balked at the very idea of food, and he faily buzzed with energy in the cool air. He’d forgotten to grab a jacket in his haste to leave the flat but was thankful for that fact, as every time his thoughts (against his will) returned to Sherlock’s eyes and the way his body had tilted (had it really? Had John imagined it?) he felt flushed.

Jesus.

It was _nothing_ , John insisted to himself. Just a weird moment that he had imagined. Sherlock wouldn’t even remember this by the time he’d returned home. John had just – had too much caffeine, is all.

Eventually, many blocks later, his heart rate had come back under control and he was beginning to rationalize the incident and stow it away in the place where all repressed memories go.

Too much caffiene, then. Right.

No more tea in the afternoons for a while.


End file.
